Renewable diesel can be made from natural oils and greases (vegetable oils and animal fats) in a two-step process: Step (1) deoxygenation via hydrotreating to form n-paraffins with the removal of oxygen as H2O and/or CO/CO2 and Step (2) isomerization/cracking of the n-paraffins formed in Step 1 to produce branched diesel and jet fuel products per need.
Currently, the deoxygenation Step (1) mentioned above is carried out commercially using a single or multi-layer catalytic bed approach and using standard hydrotreating type catalysts similar to those used for petroleum desulfurization and denitrogenation applications. The catalysts are typically based on Ni, Mo and optionally P on an extruded support containing predominantly Al2O3. The catalysts are prepared as oxides during the manufacturing process and subsequently converted to the active sulfided state either with in situ or ex situ activation procedures.
Examples of other active sites that may be employed to provide the deoxygenation and hydrogenation functions are sulfided base metals such as sulfided NiMo or sulfided CoMo or sulfided NiW. A base metal is a metal which oxidizes when heated in air. In addition to nickel, molybdenum and tungsten, other base metals which may be catalyst components herein include iron, lead, zinc, copper, tin, germanium, chromium, titanium, cobalt, rhenium, indium, gallium, uranium, dysprosium, thallium and mixtures thereof. While the reference uses a NiMo catalyst, this reference does not specifically teach or exemplify Cu or Cr as a promoter.
US Patent Application No. 20110258916 teaches a hydrotreating process that is performed in presence of hydrogen and of a hydrogenation catalyst containing a support and one or more metals selected from among metals of group VIII and group VIB (Group 6—chromium group.) Paragraph [0043] therein teaches that the catalysts that can be used are all hydrogenation and hydrotreating catalysts known in the art, and containing one or more metals selected from metals of group VIII (Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt) and group VIB (Cr, Mo, W) suitably supported. While the reference teaches that NiMo is known, this reference does not directly teach or exemplify Cu and Cr. Examples therein use sulfided NiMo/Al2O3.
US Patent Application No. 20070175795 claims a catalyst for deoxygenation based on a sorbent formulation with zinc oxide and a promoter oxide in reduced state including chromium and copper. However, the formulation therein s distinct from the present invention. While the process of US '795 describes a process wherein a promoter metal is selected from the group consisting of nickel, cobalt, iron, manganese, tungsten, silver, gold, copper, platinum, zinc, tin, ruthenium, molybdenum, antimony, vanadium, iridium, chromium, and palladium, the reference suggests, but does not teach with any specificity, a promoter metal being copper or chromium.
U.S. Pat. No. 8,043,600 mentions Group VIB (Group 6) and VIII in its specification for use as catalysts for hydrotreating natural oils. Again, the reference does not teach with any specificity a promoter metal being copper or chromium.